The subject matter disclosed herein generally relates to detection of contaminants in fuel and in particular to monitoring and conditioning of gas turbine fuel.
Fuel composition, among other things, influences the corrosion and hence the life of component material in a gas turbine. Fuel may include hydro-carbon based gases and liquids that are directly combusted to produce energy. Elements in the periodic table such as sulfur, sodium, vanadium, potassium, calcium, lead, etc. that may be present as contaminants in the fuel cause degradation of alloy coatings. For example, oxides of sulfur and vanadium may react with other contaminants to form sulfates and vanadates that are corrosive at high temperatures. Typically, the presence of contaminants in fuel, such as sodium, potassium, and vanadium result in deposits from the combustion process that damage the protective surface coating of gas turbine components.
Gas turbine life is affected by corrosion of different components. Fuel composition is a significant contributor to corrosion in gas turbines. The concentration levels of elemental contaminants in the fuel influence gas turbine performance and maintenance in general. Furthermore, contaminants influence degradation of parts of the gas turbine that are exposed to hot-gas including combustors, transition pieces and turbine buckets. Contaminants contained in compressor inlet air, injected steam, and water may also contribute significantly to corrosion. Conventional methods to check for fuel contaminants include manual sampling and testing using a rotating disc emission (RDE) spectrometer. Such methods are prone to corruption of the fuel sample that may arise due to mishandling or poor sampling techniques. Frequent sampling is required at locations where fuels are susceptible to having high contaminant levels. Such frequent sampling is time consuming and labor intensive.
It is desirable to have an online fuel analysis system that provides an ability to track elemental contaminant concentrations in real time. Further, such real time monitoring of fuel would enable timely corrective action and reduce instances of unscheduled maintenance.